148 



HEATING AS APPLIED IN HORTICULTURE. 



seen, and tends greatly to strengthen the 

 joint, and prevent the escape of smoke or 

 noxious gas. 



Loudon's chamber-flue — fig. 152. The 

 leading feature in this flue, as will be 



Fig. 152. 



seen by a glance at the annexed sketch, is 

 the division of it into chambers or com- 

 partments. The one nearest the furnace 

 is 20 feet in length, the others are 10 feet. 

 These chambers are formed by placing 

 perpendicular partitions a, of bricks, from 

 the covers to within a brick and a half 

 of the bottom. The object of the intelli- 

 gent designer was, that each compart- 

 ment should be filled with smoke and 

 heat before it reached the next, and that 

 the whole flue should thus be charged 

 with heat before any escaped at the 

 chimney-top. This flue was of the usual 

 width, but it was found to be soon choked 

 with soot at the dip b. It has been long- 

 since disused, as well as the hot-air flue 

 on the top of it, c. As there is such a 

 rage at the present time for heating by 

 means of hot air, we shall not be much 

 surprised to see the hot-air flue of Mr 

 Loudon brought again into use by some 

 of the advocates for that mode of heating. 



The Dalkeith chamber-flue — fig. 153 — is 

 4 feet wide, and 3 feet high, and is divided 



Fig. 153. 



into chambers by cross 9-inch walls, a a 

 in ground-plan — reducing the size at each 

 of these parts to 10 inches in breadth 

 and 18 inches in height. How far such 



a sized flue, under ordinary circumstances, 

 would be advisable, it is difficult to say ; 

 but there are many cases where its adop- 

 tion is of advantage. In the case at pre- 

 sent described, it forms the base of a hot- 

 water tank b, in longitudinal section, fig. 

 154, and is intended to communicate heat 



Fig. 154. 



to the water, as well as by its sides to the 

 atmosphere of the house. The sides are 

 4 inches thick— that is, the breadth of 

 one brick — excepting opposite to the par- 

 titions. The roof of the flue is formed 

 by a series of arches — vide longitudinal 

 section — having for their support the 

 cross partitions ; and over them, when 

 levelled up, is the bottom of the tank 

 laid in cement. The shaded square in 

 the longitudinal section represents air 

 flues which pass right through, and, com- 

 municating with the vacuity between 

 the flue and front wall, admit the air 

 from the ventilators in that wall into the 

 body of the house in a genially heated 

 state. 



This flue draws well, and very little 

 heat escapes at the chimney-top, although 

 the whole length from the boiler to the 

 top is only 67 feet. The other cases to 

 which we think flues of this magnitude 

 and construction applicable, are pine or 

 other pits requiring bottom heat ; and, if 

 care be taken to keep an aperture of a 

 few inches between the flues and the side 

 walls, to prevent the loss of heat by ab- 

 sorption, we are satisfied that a great 

 saving in fuel would be the result. The 

 contractions at the partition walls increase 

 the draught, while the heat has time and 

 space to expand itself in the chambers, 

 and slowly to find its way into the house. 

 So great a mass of building, when once 

 heated, will retain its temperature a long 

 time. Such a method, however, should 

 only be applied to pits or houses where 

 the temperature is required to be kept 

 both uniform and high. Our opinion is, 

 that this flue will heat the tank suffi- 

 ciently for tropical plants without the aid 



